How can I tell what diseases I have?

Solution 1:

Basically, what you can do is go under the main menu, select the magic tab and click Active Effects. If you currently have a disease, the effects will show up here in red (connoting a negative effect). Here are the diseases that you can contract in Skyrim as per the Elder Scrolls Wiki:

• Ataxia: Lockpicking & Pickpocket become 25% harder. This disease is contracted from traps and Skeevers.

• Black Heart Blight (Dragonborn DLC only): Drains 10 points from carry weight.

• Bone Break Fever: -25 Stamina. Contracted from Traps, Bears.

• Brain Rot: -25 Magicka. Contracted from Traps, Hagraven

• Droops (Dragonborn DLC only): One-handed and two-handed weapon damage is 15% lower. Contracted from Ash Hoppers.

• Rattles: Stamina recovers 50% slower. Contracted from Traps and Chaurus

• Rockjoint: 25% less effective with melee weapons. Contracted from Traps, Wolves and Foxes

• Sanguinare Vampiris: -25% health, progresses to Vampirism. Contracted from Vampires

• Witbane: Magicka recovers 50% slower. Contracted from Traps and Sabrecat.

• Lycanthropy: Transformation into a Werewolf.

Solution 2:

It depends on where you got it from. The best way to tell which disease you have is to (if your on the 360 like i am) press B switch over to Magic, and go to Active Effects. It will tell you which kind of disease you have.